Generate lighting causes hard split lines in textures

Hi everyone!
As the title suggests, I have loaded textures into the mesh of a house in Unity (said textures don’t cause visual problems neither in Blender nor in Substance Painter) and when I hit Generate Lighting in the Lighting tab it causes a very visible split line in the floor (as if there was some kind of crack in it).
I’m totally lost on what might be causing it… any ideas?

Found out turning off Stitch Seams in the Mesh Renderer of the OBJ did the trick for me. Leaving here in case anybody needs it. Hope it’s the proper way to do it and not some kind of monkey-typewriter type of bodge.

Looking for answers on this, then figured out the issue so I figured I’d explain the reasoning.

Your vertices in your 3d modelling program need to be on the exact same micro-unit in order for lighting not to glitch out. This happens with flat surfaces more often. For instance in Blender my Z coordinates were off by a micro-fraction of its adjacent vertices.